import java.util.*;
public class Average3 {
    public static void main(String[] args) {
            Scanner console = new Scanner(System.in);
            double sum = 0;
            int count = 0;
            while (true) {
                try {
                    int number = console.nextInt();
                    if (number == 0) {
                        break;
                    }
                    sum += number;
                    count++;
                } catch (InputMismatchException ex) {
                    System.out.printf("略过非整数输入:%s%n", console.next());
                }
            }
            System.out.printf("平均 %.2f%n", sum/count);
    }
}